Alternating-current solenoid.



G. A. BURNHAM.

ALTERNATING CURRENT SOLENOID.

APPLICATION FlLED SEPT. 28. e.

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Mm. Jg' .z. h /iwm 'UNITED STATES PATENT OFFICE.

GEORGE A. BURNHAM, OF SAUGUS, MA-SSACI-IUSETTS, ASSIGNOR TO SEARS B. CONDIT, JR.,

OF BROOKLINE, MASSACHUSETTS.

ALTERNATING-CURRENT SOLENOID.

Specifieation of Letters Patent.

Pateted May 21, 1918.

Application filed September 28, 1916. Serial No. 122,'776.

To all 'whom z't may conccm:

Be it known that I, GEORGE A. BURNHAM, a citizen of the United States, residing at Saugus, in the county of EsseX and State of Massachusetts, have invented an Improvement in Alternating-Current Solenoids, of which the following is a speccation.

This invention relates to alternating current solenoids, and has for its object the Construction of an improved form of solenoid adapted to be associated with a circuit-breaker or switch of any usual or suitable structure, and which is simple, may be easily and cheaply manufactured, and is adapted to operate efl'ectively when the condition of the circuit requires it, 'and the usual humming noise, due to the alternations of the current, is reduced to such an extent as to be inconsequential.

Figure 1 is a side elevation and partial vertical section of an alternating current solenoid enbodying this invention.

Fig. 2 is a plan View of a supporting spring for the winding which may be e'mployed.

10 represents the solenoid winding or coil which is arranged between the heads 12, 12, and is fixed to a center tube 13 of brass or other non-magnetic material. aid tube eX- tends at each end beyond the heads. lVithin the tube 13, at its upper end-portion, the top core-piece 15 is arranged, which is secured to said tube by rivets or other suitable means, thus the winding and tube and top core-piece are rigidly attached together.

The tube with its attached elements is disposed in an iron shell or case 20, of any suitable formation, and the upper end-portion of the tube and core-piece is loosely arranged in a center hole in the top wall of said case, and hence is movable freely therein, in a vertical direction. Also, within the tube 13, a relatively movable core-piece 25 is arranged, said core-piece being made of slightly lesser diameter than the internal diameter of the tube, so as to be freely inovable therein. Sad movable core-piece has attached to its upper end a stem 26, which is eXtended vertically through a center hole 27, extended through the top core-piece, and is movable longitudinally therein, and said stern hasat its upper end a head 28, which is adapted to limit the downward movement of the core-piece 25 when the winding is deeiie gized, and the core-piece is in retracted position.

The winding rests upon a fiat spring ele ment 30, which, as shown in Fig. 2, comprises an intermediate circular portion with laterally eXtended end-portions, and said circular portion engages the lowernost head 12 o the winding and encircles the tube to form a lower guide therefor, and the extremities of the end-portions freely enter recesses 31 formed in the case, and said spring is adapted to be held in place by an endpiece 35, which is attached to the bottom of the case, said end-pece being extended over the recesses which receive the extremities ot the end-portions of the spring.

When an alternating current of sufiicient value is impressed on the winding, the movable core-piece is moved into and held in attracted position, as representecl by full lines, Fig. 1, but, when the current value falls below a predetermined value, said core-piece falls into the dotted-line position, such downward movement being limited by the head on the stem of the core-piece.

The top core-piece and the relatively inovable core-piece are adapted to function as a single element when the current fiows through the winding of sufiicient voltage to attract the movable core-piece and hold the two core-pieces in engagement.

lVhen the current fiows through the winding and the relatively movable core-piece is attracted, the magnetic centers of the winding of the combined core-pieces may be in-` dicated at 50, and under such conditions, the combined core-pieces and the winding will all vibrate bodily in the shell or case, and all said elements will vibrate in unison or appoximately so, and any relative variation in the vibrations will be so slight that they will not be sufiicient to produce a hummiug sound of any consequence.

The magnetic center of the coil in the prior art is stationary, and as there is a tendency for the magnetic center of the core-piece to coincide with the magnetic center of the coil, it is evident that with a single phase alternating current there is a tendency for the core-pieces to disengage as the current passes through Zero and return to attracted position when the current reaches its maximum value. Such"an arrangement results in an undesirable noise. It is evident that if the magnetic center of the core-pieces and the magnetic center of the coil are incoincidence,-or if the distance between these two centers is substantially constant', it is evident there will be no practical separation between the relatively movable'core-piece and the top core-piece when the current passes' through maximumto zero. Therefore, this arrangement and operation of the device will be practically noiseless;

I claim 1. An alternating current solenod comprising a winding and support therefor, yielding means interposed between said windingand support'permitting a movement' of said wnding relative to said supp'ort, a

able core-piece in engagement with the top' core-piece.

2. An alternatng current solenod comprisnga windng, and support therefor,

means interposed between said winding' and support' permittng a movement' of SLlCl winding relative to said support, a tube,

and a top core-piece all rigidly connected" together', a relatively-movable core-piece arranged within the tube and adapted for engagement with the top core-piece, said winding and the elements connected therewith and the novable core-piece all adapted to vibrate subst'antially in' unison when an alternating current fiows through the winding of sufiicent voltage to cause the movable core-piece to be held in eng-agement withthe top core-piece.-

3. An alternating current solenoid comprising a shell' having a center hole in its top wall, a winding arranged in the shell, a tube to which said winding is fiXed,-the end's of which eXtend beyond the ends of the winding, the upper end of said tube extending through the center hole of the shell, a top core-piece arranged within and fixed to the upper end-portion of the tube, a relatively-movable core-piece arranged in said tube below the top core-piece having a headed stern WhicheXtends through the hole in the top core-piece, and a supporting-spring connected with the shell adaptedto support the winding.

4. An alternating current solenoid comprising an iron shell havinga guide-hole inits top-wall, a winding arrangedin said shell, a tube to which said winding is secured, the upper end of whichis arranged in and guided by the hole in said shell, a top core-piece arranged in the upper end-portion of said tube and securcd thereto, a relatively-movable core-piece arranged within the tube, saidcore-piece being movable into and out ofengagement with the top corepiece, a spring adapted to yieldingly support' the windng having a circular portion intermediate its length which encircles the tube andsser ves as a guide for the lower end thereof, the winding, tube and core-pieces being adapted to vibrate substantially in unison when an alternating current fiows through the winding of a voltage sufiici'-3`n't` to cause'the r'elati'vely-movable core-piece' 'to be held in engagement' with' the top corepie'ce;

5. An" alternating current solenoidcomprising' a winding, a top core-piece rigidly connected'thereto, and a relatively movable bottom core-piece, and means'for'maintainingjthe'magnetic Centers ofthe winding and core-pieces in approximately a fixed relation to each other when' an alternating: current flows through .the windingof a Value sufiicient to cause the relatively movable corepiece to engagethetop' core-piece.

6. An' alternating p current* solenoid comprising'a support", a coilr'elatively movable with respect-to said support and a* core relatively movable with respect to' said' coil, whereby said core and coil are adapted for simultaneous vbration under the influence of an alternating'current,

7. An alternating" current solenoid, in'- cluding a coil, a support therefor, yielding means nterposed between said* coiland support and a core movably arranged within` said coil, said coil' and core adapted'for substant'ially smultaneous motion under the influences of an alternating current. I

8. An alternating current magnet', including a support', a core piece relatively movable with' respect to said' support, a winding associated therewith, a' core' relatively movable with respect to said core' piece, and means permitting the substantially simul taneous vibration of said core piece and movable core under the influence of an alternat'ing current. V

9. An alternating current magnet including a winding, a support therefor, a' core piece associated with said winding, means supporting said core piece aclmitting; of movement the'reof relative to said support,a core movably disposed withrespect to said core piece and adapted' tobe restrained from free movement in one direction by said core piece in the energized condition of said winding, said movable mounting of said core piece permitting the substantially simultaneous vibrationof said core piece' and core relative' to said" support under the influence of'an alternatng' fluX.

10. An alternating current solenoid comprising a support, a coil arranged thereon, a core movably arranged within' said coil and means permtting the simultaneous Viand col during the energzaton of said col 10 braton of sad core and col relatve to sad by an alternatng current.

Support under the influence of an alternat- In testmony Whereof, I have signed my ing current. name to this specficaton in the presence of 11. An alternatng current solenod comtwo subscrbng witnesses.

prsng a support, a coil supported thereby, GEORGE A. BURNHAM.

a core movably arranged within said col witnesses:

and means permittng the substantal con- DANIEL M. SELEIFFERT,

cdence of the magnetic centers of said core I'IARALD S. RAMSAY.

copies of this patent may be obtaned for five cents each, by addressng the "Commissioner of Patents, Washington, I). G. 

